Leaving a bit of a negative review about a tea room

[unspoilmykid]

On the local community website. It wasnt very nice but should I just vote with my feet and not give a bad review?

Nope. If it was bad say so. Say why. They can't improve if they don't know what's wrong. Perhaps they'll take what you say on board and save their business.

If you don't want to do it on the website, why not drop them an email/a note
through the door.

You don't have to do anything in public then!